Abstract: The present invention provides a method for purifying bacterial minicells that involves subjecting a sample containing minicells to density gradient centrifugation in a biologically compatible medium. The method optionally includes a preliminary differential centrifugation step and one or more filtration steps. The invention also provides a method for purifying bacterial minicells in which a sample containing minicells is subjected to a condition that induces parent bacterial cells to adopt a filamentous form, followed by filtration of the sample to separate minicells from parent bacterial cells. The inventive methods optionally include one or more steps to remove endotoxin from purified minicell preparations, and/or treatment of purified minicell preparations with an antibiotic. Additionally, the invention provides purified minicell preparations, prepared according to the foregoing methods, and containing fewer than about 1 contaminating parent bacterial cell per 107, 108, 109, 1010, or 1011 minicells.

Abstract: A composition comprising recombinant, intact minicells that contain a therapeutic nucleic acid molecule is disclosed. Methods for purifying a preparation of such minicells also are disclosed. Additionally, a genetic transformation method is disclosed, which comprises (i) making recombinant, intact minicells available that contain a plasmid comprised of a first nucleic acid segment, and (ii) bringing the minicells into contact with mammalian cells that are engulfing-competent, such that the minicells are engulfed by the mammalian cells, which thereafter produce an expression product of the first nucleic acid segment.

Abstract: A composition comprising intact killed bacterial cells that contain a therapeutic nucleic acid, a drug or a functional nucleic acid is useful for targeted delivery to mammalian cells. The targeted delivery optionally employs bispecific ligands, comprising a first arm that carries specificity for a killed bacterial cell surface structure and a second arm that carries specificity for a mammalian cell surface receptor, to target killed bacterial cells to specific mammalian cells and to cause endocytosis of the killed bacterial cells by the mammalian cells. Alternatively, the delivery method exploits the natural ability of phagocytic mammalian cells to engulf killed bacterial cells without the use of bispecific ligands.

Abstract: The present invention provides a method for purifying bacterial minicells that involves subjecting a sample containing minicells to density gradient centrifugation in a biologically compatible medium. The method optionally includes a preliminary differential centrifugation step and one or more filtration steps. The invention also provides a method for purifying bacterial minicells in which a sample containing minicells is subjected to a condition that induces parent bacterial cells to adopt a filamentous form, followed by filtration of the sample to separate minicells from parent bacterial cells. The inventive methods optionally include one or more steps to remove endotoxin from purified minicell preparations, and/or treatment of purified minicell preparations with an antibiotic. Additionally, the invention provides purified minicell preparations, prepared according to the foregoing methods, and containing fewer than about 1 contaminating parent bacterial cell per 107, 108, 109, 1010, or 1011 minicells.

Abstract: The present invention provides a method for purifying bacterial minicells that involves subjecting a sample containing minicells to density gradient centrifugation in a biologically compatible medium. The method optionally includes a preliminary differential centrifugation step and one or more filtration steps. The invention also provides a method for purifying bacterial minicells in which a sample containing minicells is subjected to a condition that induces parent bacterial cells to adopt a filamentous form, followed by filtration of the sample to separate minicells from parent bacterial cells. The inventive methods optionally include one or more steps to remove endotoxin from purified minicell preparations, and/or treatment of purified minicell preparations with an antibiotic. Additionally, the invention provides purified minicell preparations, prepared according to the foregoing methods, and containing fewer than about 1 contaminating parent bacterial cell per 107, 108, 109, 1010, or 1011 minicells.

Abstract: Intact, bacterially-derived minicells can safely introduce therapeutically effective amounts of plasmid-free functional nucleic acid to target mammalian cells. To this end, functional nucleic acid can be packaged into intact minicells directly, without resort to expression constructs, the expression machinery of the host cell, harsh chemicals or electroporation.

Abstract: The present invention provides a method for purifying bacterial minicells that involves subjecting a sample containing minicells to density gradient centrifugation in a biologically compatible medium. The method optionally includes a preliminary differential centrifugation step and one or more filtration steps. The invention also provides a method for purifying bacterial minicells in which a sample containing minicells is subjected to a condition that induces parent bacterial cells to adopt a filamentous form, followed by filtration of the sample to separate minicells from parent bacterial cells. The inventive methods optionally include one or more steps to remove endotoxin from purified minicell preparations, and/or treatment of purified minicell preparations with an antibiotic. Additionally, the invention provides purified minicell preparations, prepared according to the foregoing methods, and containing fewer than about 1 contaminating parent bacterial cell per 107, 108, 109, 1010, or 1011 minicells.

Abstract: Intact, bacterially-derived minicells can safely introduce therapeutically effective amounts of plasmid-free functional nucleic acid to target mammalian cells. To this end, functional nucleic acid can be packaged into intact minicells directly, without resort to expression constructs, the expression machinery of the host cell, harsh chemicals or electroporation.

Abstract: A composition comprising recombinant, intact minicells that contain a therapeutic nucleic acid molecule is disclosed. Methods for purifying a preparation of such minicells also are disclosed. Additionally, a genetic transformation method is disclosed, which comprises (i) making recombinant, intact minicells available that contain a plasmid comprised of a first nucleic acid segment, and (ii) bringing the minicells into contact with mammalian cells that are engulfing-competent, such that the minicells are engulfed by the mammalian cells, which thereafter produce an expression product of the first nucleic acid segment.

Abstract: A composition comprising intact minicells that contain a drug molecule is useful for targeted drug delivery. One targeted drug delivery method employs bispecific ligands, comprising a first arm that carries specificity for a bacterially derived minicell surface structure and a second arm that carries specificity for a mammalian cell surface receptor, to target drug-loaded minicells to specific mammalian cells and to cause endocytosis of the minicells by the mammalian cells. Another drug delivery method exploits the natural ability of phagocytic mammalian cells to engulf minicells without the use of bispecific ligands.

Abstract: A composition comprising intact killed bacterial cells that contain a therapeutic nucleic acid, a drug or a functional nucleic acid is useful for targeted delivery to mammalian cells. The targeted delivery optionally employs bispecific ligands, comprising a first arm that carries specificity for a killed bacterial cell surface structure and a second arm that carries specificity for a mammalian cell surface receptor, to target killed bacterial cells to specific mammalian cells and to cause endocytosis of the killed bacterial cells by the mammalian cells. Alternatively, the delivery method exploits the natural ability of phagocytic mammalian cells to engulf killed bacterial cells without the use of bispecific ligands.

Abstract: A composition comprising recombinant, intact minicells that contain a therapeutic nucleic acid molecule is disclosed. Methods for purifying a preparation of such minicells also are disclosed. Additionally, a genetic transformation method is disclosed, which comprises (i) making recombinant, intact minicells available that contain a plasmid comprised of a first nucleic acid segment, and (ii) bringing the minicells into contact with mammalian cells that are engulfing-competent, such that the minicells are engulfed by the mammalian cells, which thereafter produce an expression product of the first nucleic acid segment.

Abstract: Intact bacterially derived minicells containing functional nucleic acids or plasmids encoding functional nucleic acids can reduce, in targeted mammalian cells, drug resistance, apoptosis resistance, and neoplasticity, respectively. Methodology that employs minicells to deliver functional nucleic acids, targeting the transcripts of proteins that contribute to drug resistance or apoptosis resistance, inter alia, can be combined with chemotherapy to increase the effectiveness of the chemotherapy.

Abstract: The present invention provides a method for purifying bacterial minicells that involves subjecting a sample containing minicells to density gradient centrifugation in a biologically compatible medium. The method optionally includes a preliminary differential centrifugation step and one or more filtration steps. The invention also provides a method for purifying bacterial minicells in which a sample containing minicells is subjected to a condition that induces parent bacterial cells to adopt a filamentous form, followed by filtration of the sample to separate minicells from parent bacterial cells. The inventive methods optionally include one or more steps to remove endotoxin from purified minicell preparations, and/or treatment of purified minicell preparations with an antibiotic. Additionally, the invention provides purified minicell preparations, prepared according to the foregoing methods, and containing fewer than about 1 contaminating parent bacterial cell per 107, 108, 109, 1010, or 1011 minicells.

Abstract: A method of targeting bacterially-derived, intact minicells to specific, non-phagocytic mammalian cells employs bispecific ligands to deliver nucleic acids efficiently to the mammalian cells. Bispecific ligands, comprising (i) a first arm that carries specificity for a bacterially-derived minicell surface structure and (ii) a second arm that carries specificity for a non-phagocytic mammalian cell surface receptor are useful for targeting minicells to specific, non-phagocytic mammalian cells and causing endocytosis of minicells by non-phagocytic cells.

Abstract: A composition comprising recombinant, intact minicells that contain a therapeutic nucleic acid molecule is disclosed. Methods for purifying a preparation of such minicells also are disclosed. Additionally, a genetic transformation method is disclosed, which comprises (i) making recombinant, intact minicells available that contain a plasmid comprised of a first nucleic acid segment, and (ii) bringing the minicells into contact with mammalian cells that are engulfing-competent, such that the minicells are engulfed by the mammalian cells, which thereafter produce an expression product of the first nucleic acid segment.

Abstract: The present invention provides a method for purifying bacterial minicells that involves subjecting a sample containing minicells to density gradient centrifugation in a biologically compatible medium. The method optionally includes a preliminary differential centrifugation step and one or more filtration steps. The invention also provides a method for purifying bacterial minicells in which a sample containing minicells is subjected to a condition that induces parent bacterial cells to adopt a filamentous form, followed by filtration of the sample to separate minicells from parent bacterial cells. The inventive methods optionally include one or more steps to remove endotoxin from purified minicell preparations, and/or treatment of purified minicell preparations with an antibiotic. Additionally, the invention provides purified minicell preparations, prepared according to the foregoing methods, and containing fewer than about 1 contaminating parent bacterial cell per 107, 108, 109, 1010, or 1011 minicells.